Loudspeakers are required to have various configurations depending on usage. For example, a vehicle-mounted loudspeaker installed in a dashboard of a vehicle, a ceiling of a vehicle or the like is required to be particularly as thin as possible.
To decrease the thickness of a loudspeaker, in general, it is necessary to decrease the thickness of a diaphragm, to shorten a bobbin on which a voice coil is wound in a winding axis direction of the voice coil, or to decrease the thickness of a magnetic circuit. On the other hand, it is difficult for a loudspeaker having a thin thickness to ensure the rigidity of a diaphragm or to ensure a sound pressure level of a sound outputted from the loudspeaker.
As citation list information relating to the invention of the present application, for example, Unexamined Japanese Patent Publication No. 56-56095 and Unexamined Japanese Patent Publication No. 2011-35812 have been known.